The present invention involves the concept of networking networks, a procedure called network interconnection, or internetting.
Internetting was first explored in the early 1970's by DARPA. The agency sought ways to interconnect different packet networks so that computers using them could communicate without concern for which kind of and how many networks made the interconnections. Special processors called gateways (or internetworking units) were developed to connect two or more networks and to pass packet traffic from one network to the next.
To send the information, a processor creates packets including the source and destination addresses and encapsulates the packets in the format required by its local network. The computer then routes the packets to the appropriate internetworking unit (IWU) for further processing and transmission.
Two significant tasks of IWU's have been identified as the buffering and switching of packets. The buffering task involves reception of packets into the main buffers and transmission of these packets out of the main buffers. The switching task is to determine the destination of the transmission and to modify the formats of the packets as required by the neighboring network protocols.
The buffering and switching, commonly referred to as store-and-forward, are necessary in the packet-switching environment due to network differences such as media speeds, operating protocols, and network traffic.